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How to calculate the electrode potential value for REDOX reaction with examples

Answer Text:
THE ELECTRODE POTENTIAL VALUE FOR A REDOX REACTION
- Is usually calculated as the sum of the E#theta# value for the half cells involved.
Note:
- If the sum is positive then the reaction can occur simultaneously;
- If the value of the sum is negative the reaction cannot occur;
Sample calculations
1. #Cu^(2+)#can oxidize Zinc but #Zn^(2+)# cannot oxidize Cu;

- The overall reaction is positive, hence zinc can be oxidized by copper (II) ions, and hence reaction occurs;

- The overall #Etheta# is negative; thus #Zn^(2+)# cannot oxidize Cu to #Cu^(2+)# (Cu cannot reduce Zn 2+ to Zn); and hence the reaction cannot occur.
2. Can chlorine displace bromine form bromide solution?

- The overall #Etheta# for the reaction is positive, so chlorine can displace bromine from a bromide solution.